Monday, May 31, 1999 Published at 16:09 GMT 17:09 UKUKPolice given key to unsolved murdersCriminals cannot give alibis for their DNAHundreds of unsolved murders dating back 30 years could be cleared up by an advance in genetic fingerprinting which is being made available to police.

Detectives from all over the UK will soon have access to the technique which has been developed by the Forensic Science Service (FSS) in Birmingham.

It is capable of providing DNA profiles of criminals from a single flake of skin or a tiny speck of blood.

Scientists have even managed to obtain sample material from watch straps, ear rings and even shirt collars.

There is even evidence that DNA material can be left over after a handshake.

50% success rate

In Australia, where the technique was pioneered, about 100 cases have been reopened and there have been at least 50 successful prosecutions.

The technique will also enable police to identify serial killers.

Detectives at the National Crime Faculty at Bramshill, Hampshire, have identified several "clusters" of unsolved murders which could be the work of the same individual.

Among them are a series of prostitute murders in London, the Midlands and Scotland.

Dawn Shields...body found in the Peak District

Dawn Shields, 19, was abducted from her beat in Sheffield's red light district, stripped, strangled and dumped in a shallow grave at Mam Tor in the Derbyshire Peak District in May 1994. Her killer is still free.

Ever since the Polymerase chain reaction technique was first developed in the 1980s, scientists have been working on taking DNA from smaller and smaller pieces of evidence.

Police will now re-examine microscopic fragments which were previously thought to be too small to use.

Reopening old crimes

Scientists say they should be able to obtain genetic profiles from biological material - blood, saliva, hair or semen - taken from crime scenes up to 30 years ago.

DNA is a tough material by nature and researchers have been amazed by its stubborness.

A spokeswoman for the FFS said: "We will be looking at the same types of material in terms of biological
traces but it means that even if there is not much of it, or it is degraded, the new technology gives a much, much better chance of getting a profile.

"It is more powerful, more sensitive and more discriminatory than before."

'Excellent results'

Schoolgirl Nayntara Ali was murdered five years ago

She said: "We have had excellent results with the technology used at the moment but this is taking it a step further."

The new technique is to be made available next week and will allow police to reopen hundreds of unsolved cases .

Detectives in east London will want to re-examine the case of 11-year-old Nayntara Ali, who was murdered on her way home from school in Forest Gate, east London. Her body was found rolled up in a carpet in a disused yard.

Rachel Nickell...her killer remains at large

Derbyshire police are expected to be among the first to avail themselves of the new technique. They are still trying to trace the killer of 24-year-old teacher Barbara Mayo, whose battered body was found in woods off the M1 in 1970.

Another high profile case which will no doubt be revisited is the Rachel Nickell murder on Wimbledon Common in 1992.

High profile cases

The FSS has been trialling its Low Copy Number (LCN) test since january, using samples of evidence from about 70 cases, mostly unsolved high profile murders and rapes.

But the new technique has yet to be tested in court and some independent forensic scientists fear it could be easily contaminated.

LCN is based on the work of Dr Roland Van Oorschot at the Victoria Forensic Science Service in Australia.